The present invention relates to a novel adamantane derivative, and more particularly, to a 1,3-adamantanedicarboxylic acid-bis(2xe2x80x2-alkyl-2xe2x80x2-adamantyl) ester compound which is useful not only as a photoresist additive but also as pharmaceuticals, an agrochemical intermediate, a resin additive (heat resistance improver) and the like.
Adamantane and analogues, which are imparted with extremely stable carbon skeleton and besides, exhibit peculiar functions, have hitherto been employed for a variety of purposes, particularly for an optical disc base, optical fiber, lens and the like from the aspect of their optical characteristics and heat resistance {refer to Japanese Patent Laid-Open Application Nos. 302077/1997 (Heisei 9)} and 305044/1994 (Heisei 6)}.
In addition, an adamantane ester and analogues is utilized as a photoresist additive by taking advantage of their responsiveness to an acid and transparency for ultraviolet ray.
Research and development have heretofore been made by the present inventors on a dicarboxylic acid diadamantyl analogue compound {refer to Japanese Patent Laid-Open Application No. 252149/1999 (Heisei 11)}, a (bis)adamantane based compound and a process for the production thereof {refer to Japanese Patent Application No. 15341/2000 and an adamantane derivative such as a bisadamantane derivative {refer to Japanese Patent Application No. 65930/2000.
All of the above-cited compounds is a compound in which two adamantane skeletons are bonded to each other directly or through several carbon bonds or several ester bonds, but nothing is known yet about a trisadamantane based compound in which adamantane skeletons are linked with two ester bonds.
An object of the present invention is to provide a trisadamantane based compound which is expected to expand its usage and application typified by a photoresist additive by taking advantage of not only extremely stable carbon skeleton but also responsiveness to an acid and transparency for ultraviolet ray.
In particular, the above-mentioned trisadamantane based compound is expected to have a profound effect on responsiveness to an acid per unit weight by virtue of its having two ester groups in comparison with a monoester adamantane compound. As the result of intensive extensive research and investigation accumulated by the present inventors in order to achieve the object as mentioned above, it has been found that a 1,3-adamantanedicarboxylic acid-bis(2xe2x80x2-alkyl-2xe2x80x2-adamantyl) ester compound as a trisadamantane based compound, which is a novel compound that has never been disclosed in any literature, is adaptable to the above-mentioned object.
Specifically, the present invention is concerned with a 1,3-adamantanedicarboxylic acid-bis(2xe2x80x2-alkyl-2xe2x80x2-adamantyl) ester compound represented by the general formula (I): 
wherein R1 and R2 are each an alkyl group having 1 to 8 carbon atoms; X1 and X2 are each hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, carboxyl group or COOR3 in which R3 is an alkyl group having 1 to 8 carbon atoms.